Hydrocarbon fuel reformers are used in fuel cell power plants. They take raw hydrocarbon fuel such as natural gas, propane, or naphtha and catalytically convert the raw fuel to a hydrogen rich fuel gas suitable for use as an anode fuel. Raw fuel is percolated through catalyst beds which are contained in tubes mounted within the reformer housing.
Catalytic conversion is carried out at elevated temperatures in the range of 800 F. to 1700 F. The reformer includes a pressure vessel as the reformer shell within which a burner is operated to establish these elevated temperatures.
Reactors are in the form of bayonet tubes with an upward flow in the outer portion through the catalyst bed and a downward flow through the inner portion, providing some counterflow heat recovery to the reformed gas from the incoming gas. The flue gas passes in heat exchange relationship with the outer surface of the bayonet tubes. It is maintained in close contact therewith by surrounding sleeves with a baffle or seal plate forcing the flue gas through its allotted area.
In the past the components of the reformer gas flowpath have been supported from the side of the shell. This requires additional structure for the low pressure shell since it must now carry additional load. Furthermore, the shell penetrations for the reformed gas outlet have been expensive because of the differential movement caused by differential expansion during operating conditions.